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| class Solution {
public int findInMountainArray(int target, MountainArray mountainArr) {
int peakIndex = findPeakIndex(mountainArr);
int index = binarySearch(mountainArr, 0, peakIndex, true, target);
if (index != -1) {
return index;
} else {
return binarySearch(mountainArr, peakIndex, mountainArr.length() - 1, false, target);
}
}
private int binarySearch(MountainArray mountainArr, int left, int right, boolean asc, int target) {
while (left <= right) {
int mid = (left + right) >>> 1;
int midVal = mountainArr.get(mid);
if (midVal < target) {
if (asc) {
left = mid + 1;
} else {
right = mid - 1;
}
} else if (midVal > target) {
if (asc) {
right = mid - 1;
} else {
left = mid + 1;
}
} else {
return mid;
}
}
return -1;
}
private int findPeakIndex(MountainArray mountainArr) {
int left = 0, right = mountainArr.length() - 1;
while (left < right) {
int mid = (left + right) >>> 1;
int midVal = mountainArr.get(mid), nextVal = mountainArr.get(mid + 1);
if (midVal < nextVal) {
left = mid + 1;
} else {
right = mid;
}
}
return left;
}
}
|